1. Selective ozone treatment of PDMS printing stamps for selective Ag metallization: A new approach to improving resolution in patterned flexible/stretchable electronics.
- Author
-
Francis G, Stuart BW, and Assender HE
- Abstract
Hypothesis: Selective ozone treatment of Polydimethylsiloxane (PDMS) print-stamps may facilitate local de-wetting of Krytox®1506 oil; the resulting printed pattern can be used as a masking liquid during roll-to-roll vacuum-metallization, exemplified with Ag. This novel method may exploit high-throughput manufacture without chemical etchants or elevated temperatures for thin-film electronics., Experiments: The mechanism for selective wetting arose from O
3 treatment of PDMS through a shadow-mask to vary surface-energy due to formation of polar silanol (Si-OH) replacing surface methyl groups leading to contact angle reduction from 40°-9° for oil on PDMS. Oiled PDMS was (1) metalized itself and (2) used as a stamp to print onto polyethylene-terephthalate, consisting of oil pick-up/de-wetting/transfer-to-substrate/metallization., Findings: Ag (520-568 nm) thick was deposited outside oiled regions, surpassing ~20 μm resolution of commercial printing. On metalized PDMS, minimum line widths were 2.6 μm (with 10 μm edge-grading from centrifugal oil spreading) or widths of 24 μm (no Ag grading) following spin-coating/roll-coating oil respectively. The progressive effect of thinning oil via five successive stamp-to-substrate impressions, produced line widths of 14 μm (with graded edge of 7.6 μm via spreading from stamp-substrate compression). Developments may reduce reliance on laser engraving/photocuring, and could enhance micro-contact printing through liquid dynamics vs. topographical relief structures., Competing Interests: Declaration of Competing Interest A patent has been filed for the work submitted in this manuscript. UK patent application number is No. 1914539.0 – Printing of Flexible Circuits for Oxford University Innovation Limited., (Copyright © 2020 Elsevier Inc. All rights reserved.)- Published
- 2020
- Full Text
- View/download PDF